The present invention relates generally to extruded products. In one aspect, the invention relates to extruded gel products while in another aspect, the invention relates to an apparatus for extruding a gel product. In yet another aspect, the invention relates to a method for making a firm, flexible gel product suitable as a feed for animals, particularly carnivores. In still another aspect, the present invention relates to a method for making the gel product in the general shape of a natural prey animal of the carnivore.
Large quantities of animal feed are required by the many and varied zoological gardens of the world that are responsible for the breeding and care of a wide assortment of animals. Feeding these animals, particularly those that are carnivorous, can be a costly and labor intensive process that can provide numerous challenges. Ensuring that each animal receives a properly balanced diet in a timely and efficient manner requires careful planning, reliable food sources, trained personnel, and not infrequently, good fortune.
To diminish the problems associated with the feeding of large numbers of carnivorous animals, the operators of these gardens and similar establishments, e.g., breeding farms, entertainment facilities, etc., search continuously for manufactured sources of animal protein to replace natural sources of animal protein, e.g., meat, poultry, fish, and the like, fresh or frozen. Manufactured sources of animal protein are generally less expensive, and are available in bulk quantities. Additionally, they are generally easier to transport and store, and often are easier to tailor with respect to nutritional content than are natural sources of animal protein. Moreover, the sources of some natural animal protein, e.g., fish from the oceans, continue to dwindle. This in turn restricts the availability of such protein and raises its price.
While many animals, carnivorous and non-carnivorous alike, will consume fungible food items such as grain, various liquids, pellets or other processed food stuffs, most carnivores require at least some portion of their diet to be in the general shape and texture of their natural prey, e.g., the carcass or part of a carcass of a fish, bird, mammal, etc. With respect to fish-eating animals, the size, shape and texture of the fish is important to its acceptance as a food.
Animal feed gels are conventionally produced by pouring a mixture comprising at least one gelling agent, at least one protein source and water into a mold, allowing the mixture to set, and then removing the gel from the mold for packaging, shipping, storage and/or use. The finished gel product has sufficient structural integrity that it can be handled in a routine manner without breakage, e.g. it can be fed by hand to an animal without breaking in the hand of the feeder.
Extruded products and their methods of manufacture are known in the art, e.g., U.S. Pat. Nos. 5,948,459, 5,939,124, 5,665,419 and 4,886,440, all of which are incorporated herein by reference. Exemplary extruded products include a wide array of items, both food and nonfood. Significantly, extrusion methods of manufacture are useful in providing large quantities or numbers of product in a cost effective and automated manner. Extrusion devices for making such products are also known in the art, e.g., U.S. Pat. Nos. 4,643,660, 4,560,334, 3,743,252, and 3,674,407 (all of which are incorporated herein by reference).
According to one embodiment of this invention, a method for making a firm, flexible animal feed gel comprises the steps of:
A. Forming a liquid animal feed at a temperature above ambient temperature;
B. Passing the liquid animal feed through a pipe cooled to a temperature below the temperature of the liquid animal feed of step (A) such that the feed solidifies to a stiff, flexible gel while in the pipe; and
C. Collecting the gel as the gel exits the pipe.
The composition of the animal is feed is predominantly water containing at least one gelling agent and at least one source of protein, typically an animal-derived protein such as fish or poultry meal. Other typical ingredients include a fat source, a gum, and various vitamins, minerals and other animal health promoters.
The animal feed is typically prepared in a heated vat from which it is transferred by any conventional means, e.g., a pump, to the pipe. The length and cross-section of the pipe can vary, but it is typically 10-30 feet in length with an internal diameter of at least about one inch. The shape of the cross-section of the pipe can also vary. The length of the pipe can be straight or coiled, and the pipe can be cooled by any suitable means, e.g., encased in a jacket through which a coolant is circulated.
In another embodiment of this invention, an apparatus for extruding a firm, flexible animal feed gel comprises:
A. A pipe having an inlet end and an outlet end, the inlet adapted for receiving a liquid animal feed at a temperature above ambient temperature and the outlet end adapted for extruding a firm, flexible animal feed gel;
B. A pump for passing the liquid animal feed through the pipe;
C. A means for cooling the liquid animal feed to a temperature below the temperature of the liquid animal feed of step (A) such that the feed solidifies to a stiff, flexible gel while in the pipe; and
D. A means for collecting gel as it exits the pipe.
In one embodiment of the invention, the pump is in fluid communication with both the inlet of the pipe and a vat or similar container holding the heated liquid animal feed. In another embodiment, the pipe is straight and encased in a jacket through which a coolant is circulated while in still another embodiment, the pipe is coiled and fitted within a tank filled with a circulating coolant. In yet another embodiment, the collecting means comprises a rotating knife for cutting the gel into desired lengths as it exits the pipe. The outlet end of the pipe can be fitted with a die for forming the gel into a desired shape as it exits the pipe.